The present invention relates to a cutting method of a ceramic honeycomb formed body for cutting the ceramic honeycomb formed body substantially at right angles to the direction of throughholes.
A ceramic honeycomb structure used as a carrier for a waste gas purifying catalyst or the like is manufactured by forming a ceramic material containing ceramic powder into a honeycomb shape, cutting the thus formed body into appropriate lengths, and then, drying and firing the resultant lengths. It is therefore necessary to provide means for cutting a soft and easily deforming ceramic honeycomb formed body without affecting the shape. For such cutting, it is the conventional practice to impart a tension to a fine line 2 stretched between two pulleys 1 by a spring 3 and cutting the ceramic honeycomb formed body by causing reciprocation of this fine line in the longitudinal direction as shown in FIG. 5, or cutting the same by causing a fine line 2 in the course of rewinding the fine line 2 onto one of bobbins 8 by the rotation of servo motors 7 while imparting an appropriate tension by adjusting the torque of the servo motors 7 to the fine line 2 stretched between the bobbins 8 provided on the two servo motors 7 as shown in FIG. 6.
These conventional practices have a problem in that, because cutting is performed while moving the fine line 2 in the longitudinal direction, resistance upon cutting the outer periphery of thickness of the ceramic honeycomb formed body 5 causes a load in the moving direction of the fine line 2 on the work for cutting, resulting in a distortion in the ceramic honeycomb formed body 5. Particularly, partition walls of the honeycomb structure are showing a tendency toward a smaller thickness from the conventional value of about 150 xcexcm to a range of from 50 to 125 xcexcm or even smaller, and this leads to an increased numerical aperture of the honeycomb structure cross-section and hence to a smaller strength of the honeycomb formed body. The problem of distortion caused by cutting is thus becoming more serious than ever.
In addition to the distortion of the honeycomb formed body as a whole, deformation and collapse of the partition walls of the honeycomb structure under the downward load during cutting are becoming more serious. In order to avoid this phenomenon, it suffices to carry out cutting less strictly, but this results in a lower cutting efficiency.
Since cutting is accomplished while moving the fine line in the longitudinal direction, the fine line has a short service life, and it is necessary to frequently replace the fine line, requiring to adjust the tension every time the fine line is replaced. This seriously impairs the cutting efficiency of the ceramic honeycomb formed body.
The present invention was developed in view of these circumstances, and has an object to provide a cutting method of a ceramic honeycomb body which does not cause distortion in the ceramic honeycomb formed body and gives a cutting efficiency higher than in the conventional art.
More particularly, according to the present invention, there is provided a cutting method of a ceramic honeycomb formed body for cutting the ceramic honeycomb formed body with a fine line stretched at an appropriate tension substantially at right angles to the direction of throughholes thereof, comprising the steps of providing a cutting guide groove running through the outer periphery of the ceramic honeycomb formed body substantially at right angles to the direction of throughholes; and putting a fine line to the cutting guide groove, and cutting the ceramic honeycomb formed body only by pressing the fine line against the ceramic honeycomb formed body.
In the aforementioned cutting method, the fine line may be stretched between bobbins, and the position of the fine line used for cutting may be changed every an appropriate number of runs of cutting. Also in the above-mentioned cutting method, the cutting guide groove should preferably run through only the outer periphery. The cutting guide groove may be formed with a knife.
The aforementioned cutting method may comprise the steps of providing the cutting guide grooves at certain intervals with a knife provided in the conveying path, and cutting the ceramic honeycomb formed body with a fine line provided in the downstream of the knife in the conveying path.
The aforementioned cutting method may also comprise the steps of providing at least two cutting positions of the ceramic honeycomb formed body in the conveying path, and cutting the ceramic honeycomb formed body at a plurality of positions by means of the fine lines.